1. Field of the Invention
The present invention relates to power assisted hand tools and more particularly power assisted ratchets.
2. Description of the Prior Art
Power assisted ratchets, in numerous configurations are well known in the art. Typical air, hydraulic or electric driven ratchets fall into several well-defined classifications, including gun type impact wrenches typified by a Chicago Pneumatic CP-7XX (series impact wrenches and lever arm ratchets with the gun type impact wrenches typically used for larger size sockets and lever arm type ratchets typically for smaller size ¼″. ⅜″ and ½″ drive sockets or their metric equivalents. These lever arm ratchets also position the socket drive at the end of the ratchet in the ratchet head generally perpendicular to the long axis of the ratchet. There are also some configurations, used typically for ¼″ drive sockets, in which the socket drive is mounted at the end of the device approximately in line with the long axis of the ratchet.
In the present state of the art, power assisted lever arm ratchets have the ratchet head closely coupled to a handle which typically encloses a pneumatic motor. This closely coupled configuration is used by all of the manufacturers of power assisted lever arm type ratchets including Milwaukee Pneumatic, Chicago Pneumatic, Ingersoll-Rand, Daytona, American Rodcraft, Northern Tools and Equipment Company and many others. While all of these tools are useful embodiments of power assisted lever arm ratchets, their configuration fails to address long-standing needs including accessibility in tight environments, obstruction of the users vision when working in confined areas, wrist and hand stress and hand injuries resulting from jerking or slipping ratchets. Some manufacturers have begun to address some of these problems: for example a “cushion grip” feature is used by Northern Industrial Tools on air ratchet model numbers 158308-B952 and 158309-B952, Snap-On uses a “Santroprene” “ergonomic handle”, NAPA ratchet model NPT 6-731 features a “comfortable ergonomic motor housing” and Dayton offers a model 52273 “ergonomic reactionless ratchet” which it suggests “eliminates torque reaction, which means no more bloody or bruised knuckles when working in tight areas”. However, the current state of the art as embodied in the numerous examples cited above do not address the accessibility or view obstruction problems except by trying to make the ratchets more compact, which exacerbates the potential for injury by requiring the user's hand to be closer to the machinery. In addition, aside from the “ergonomic” grips or attempts to reduce the occurrence of torque reaction jerking or slipping of a ratchet, noting in the prior art addresses the problems of hand/arm injuries or stress and strain induced repetitive motion injuries.